michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef GFX_QUATERNION_H
michael@0: #define GFX_QUATERNION_H
michael@0: 
michael@0: #include "mozilla/gfx/BasePoint4D.h"
michael@0: #include "gfx3DMatrix.h"
michael@0: #include "nsAlgorithm.h"
michael@0: #include <algorithm>
michael@0: 
michael@0: struct gfxQuaternion : public mozilla::gfx::BasePoint4D<gfxFloat, gfxQuaternion> {
michael@0:     typedef mozilla::gfx::BasePoint4D<gfxFloat, gfxQuaternion> Super;
michael@0: 
michael@0:     gfxQuaternion() : Super() {}
michael@0:     gfxQuaternion(gfxFloat aX, gfxFloat aY, gfxFloat aZ, gfxFloat aW) : Super(aX, aY, aZ, aW) {}
michael@0: 
michael@0:     gfxQuaternion(const gfx3DMatrix& aMatrix) {
michael@0:         w = 0.5 * sqrt(std::max(1 + aMatrix[0][0] + aMatrix[1][1] + aMatrix[2][2], 0.0f));
michael@0:         x = 0.5 * sqrt(std::max(1 + aMatrix[0][0] - aMatrix[1][1] - aMatrix[2][2], 0.0f));
michael@0:         y = 0.5 * sqrt(std::max(1 - aMatrix[0][0] + aMatrix[1][1] - aMatrix[2][2], 0.0f));
michael@0:         z = 0.5 * sqrt(std::max(1 - aMatrix[0][0] - aMatrix[1][1] + aMatrix[2][2], 0.0f));
michael@0: 
michael@0:         if(aMatrix[2][1] > aMatrix[1][2])
michael@0:             x = -x;
michael@0:         if(aMatrix[0][2] > aMatrix[2][0])
michael@0:             y = -y;
michael@0:         if(aMatrix[1][0] > aMatrix[0][1])
michael@0:             z = -z;
michael@0:     }
michael@0: 
michael@0:     gfxQuaternion Slerp(const gfxQuaternion &aOther, gfxFloat aCoeff) {
michael@0:         gfxFloat dot = mozilla::clamped(DotProduct(aOther), -1.0, 1.0);
michael@0:         if (dot == 1.0) {
michael@0:             return *this;
michael@0:         }
michael@0: 
michael@0:         gfxFloat theta = acos(dot);
michael@0:         gfxFloat rsintheta = 1/sqrt(1 - dot*dot);
michael@0:         gfxFloat rightWeight = sin(aCoeff*theta)*rsintheta;
michael@0: 
michael@0:         gfxQuaternion left = *this;
michael@0:         gfxQuaternion right = aOther;
michael@0: 
michael@0:         left *= cos(aCoeff*theta) - dot*rightWeight;
michael@0:         right *= rightWeight;
michael@0: 
michael@0:         return left + right;
michael@0:     }
michael@0: 
michael@0:     gfx3DMatrix ToMatrix() {
michael@0:         gfx3DMatrix temp;
michael@0: 
michael@0:         temp[0][0] = 1 - 2 * (y * y + z * z);
michael@0:         temp[0][1] = 2 * (x * y + w * z);
michael@0:         temp[0][2] = 2 * (x * z - w * y);
michael@0:         temp[1][0] = 2 * (x * y - w * z);
michael@0:         temp[1][1] = 1 - 2 * (x * x + z * z);
michael@0:         temp[1][2] = 2 * (y * z + w * x);
michael@0:         temp[2][0] = 2 * (x * z + w * y);
michael@0:         temp[2][1] = 2 * (y * z - w * x);
michael@0:         temp[2][2] = 1 - 2 * (x * x + y * y);
michael@0: 
michael@0:         return temp;
michael@0:     }
michael@0: 
michael@0: };
michael@0: 
michael@0: #endif /* GFX_QUATERNION_H */